| Summary: | 碩士 === 高雄師範大學 === 化學系 === 97 === Two series of thermotropic compounds with 3,4,5-tris(alkoxyl)benzyl
group as the terminal unit were prepared and their thermal and liquid
crystal properties were examined by powder X-ray diffractometer,
differential scanning calorimeter and on the hot-stage of a
cross-polarizing microscope. Compounds of series I, [Cn-R3OPhCOOHSR3](n = 14, 16, 18), [Cn-R3OPhCOOH-SR350] (n = 18) and [Cn-R3OPhCOOH-SR500] (n = 14, 16), containning bisphenol A functional group moiety as the central spacer, including SR3, SR350, and SR500, formed symmetrical molecular structures,. The compounds of this series weren’t mesogenic and exhibited hexagonal columnar packing
in solid.
The series II of aliphatic ammonium salts, [Cn-R3OPhCOO-TETA+(m:1)] (n = 12, 14, 16, m = 1, 2, 3, 4, 5), were prepared by mixed 3,4,5-tris(alkoxyl)benzoic acid with triethylenetetramine in ratio from 1:1 to 5:1. All compounds of this series exhibited smectic C liquid crystal
(LC) phase, and showed wide temperature ranges about 70°C in the ratio of 1:1 and 20°C in the ratio of 5:1.
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